中文摘要：

利用全国第二次土壤普查数据,对天山北麓不同土地覆被类型下的土壤有机碳分布特征开展研究。结果表明：在0～100 cm土层天山北麓不同土地覆被类型的土壤碳密度差异显著,其均值处于3.65～35.73 kg.m-2。不同土地覆被类型的土壤碳密度垂直分布差异明显,其中耕地表层（0～20 cm）土壤碳密度占其总量的32.2%,其相邻土层的土壤碳密度占其总量比例的差值较小,最大差值仅为8.1%;高山亚高山草甸、森林和隐域植被表层（0～20 cm）土壤碳密度占其总量的40%以上;荒漠植被、裸地和稀疏植被表层（0～20 cm）土壤碳密度占其总量的比例低于37%,其中裸地与稀疏植被最低,仅为25.4%,其相邻土层土壤碳密度占其总量比例的最大差值低于4.0%。

英文摘要：

Soil carbon cycle is the focus and hotspot of the studies on global environment change.Relationship between the vertical distribution of soil organic carbon and its affecting factors was explored,especially in arid zone.In this study,the vertical distribution of soil organic carbon under different land cover types in northern piedmont of the Tianshan Mountains was studied based on the data of second national soil survey.The results showed that the mean soil organic carbon density in soil layer of 0-100 cm in depth varied from 3.65 kg·m-2 in land with sparse vegetation to 35.73 kg·m-2 in alpine and subalpine meadow.The vertical distribution of soil organic carbon density was quite different from different land cover types： the proportion of soil carbon density in soil layer of 0-20 cm in arable land accounted for 32.2% of the total soil carbon density in topsoil layer of 1 m in thickness,it was higher than 40% in alpine and subalpine meadow,forest and intrazonal vegetation surface,and lower than 37% in desert vegetation and bare land and land with sparse vegetation,in which it was 25.4% only in bare land and land with sparse vegetation.The average difference of soil carbon density between adjacent soil layers was lower than 8.1% in arable land and lower than 4.0% in bare land and land with sparse vegetation.